ATS Diesel Performance in
Arvada (CO)

Absolute terrible scammers who never ship items purchased. DO NOT buy from them. Ordered a valve body and coupler over 8 weeks ago and was told it had a 2 weeks lead time on valve body. They supplied the coupler but refuse to ship the valve body or refund the money. Im left with an angry customer whos truck is off the road. *Edit to reply to ATS DIesel's further lies in their reply* ATS Diesel reached out once initially for me to pay a $400 core charge which was paid the next day. It has been over 8 weeks and they have never refunded the money for the valve body or the core charge As can be seen in screenshot from Google Shop the order is still outstanding and has never been delivered ATS Diesel continue to lie and scam

Had to get my 2015 gmc 2500 towed into ATS bc it kept slipping and not shifting into gear . I spoke with Cody on the phone about what was happening and he told me that it was most likely the transmission. Once I got the truck to the shop Cody was very informative of all of the possible things that could be wrong and said that they would get it figured out no matter what. Yes it was the transmission and I’m grateful that it was fixed properly and in a timely manner. Cody maintained contact throughout the whole process, and I personally want to thank him for not treating me like I was a dumb woman that didn’t know what I was talking about. Made me feel comfortable and actually heard. A very refreshing feeling from a very reputable shop. I highly recommend ATS and Cody Thank you

Great company to do business with. I purchased the Allison conversion for my Ram and had them install it. Everything was done in one week! That was over a year ago. Last week I had a noise coming from the transmission, dropped it off and it was fixed within the week, no charge. Cody did a great job of keeping me informed of the progress while it was there. These guys do great work and stand behind the warranty!

I took my 2006 Dodge Cummins with 204,000 miles in for service as it was shifting badly and throwing check engine codes. Cody kept me posted as to what the problem was. It ended up being a wiring issue external to the ATS transmission. Two wires had rubbed through the insulation and were grounding out on the bell housing. This was repaired quickly and reasonably considering they had to pull the transmission in order to get to the shorted wiring. ATS has very good service and communications.

These guys are awesome! Left my truck with them for two weeks to get a Stage 5 transmission rebuild - couldn’t be happier. Cody kept me informed every step of the way and made sure my truck was ready in the agreed timeline. They also checked out some other stuff for me that I needed done. Cannot speak highly enough of their customer service and the quality of service and parts!

Cody went above and beyond to ensure warranty issue was resolved and handled communication in a very clear manner. Knew I had a 5 hour drive home and exceeded original estimate of time by over 5 hours. Very pleased with the customer service. Would recommend!

BE AWARE...... when purchasing turbos from this company. I reached out to via email to ATS diesel before purchase to verify turbo in stock I also reached out via phone call and guaranteed turbo shipped out the following day. I reached back out a couple days later since no confirmation on turbo shipped out come to find out they did not even have turbo or any parts in stock that I ordered. General manager says sorry 2 to 3 weeks out for this turbo that you purchased but hey let's sell you a smaller Turbo OEM Turbo since the 64 mm turbo is not available especially on a vehicle I have that is tuned for a bigger Turbo that also has bigger injectors also has head studs on my vehicle why would I downgrade to a smaller turbo? Not happy with the service highly suggest to make sure verify check multiple times before you purchase a turbo from this company now I'm waiting 3,400 return to me couple days to show up to my bank account to purchase another turbo for my truck that has been broken down delay in shipping. Be aware when purchasing Turbo from this company. Not happy with service at all. Miss communication within the company on inventory has delayed me weeks now for a turbo when they said they had the turbo available for ship.BE AWARE.....

I purchased their Allison conversion in 2022. The first transmission lasted about 5000 miles and completely failed. I will say they were good about their warranty and rebuilt it, however I was still out towing and the cost of pulling and reinstalling the transmission. Additionally, it took a couple months to get the replacement transmission back. That transmission has lasted roughly 50,000 miles and is getting ready to come out and go to a local transmission shop to be rebuilt. I simply cannot afford two months without the truck. I went with the Allison conversion because I thought it would be more reliable than the 68RFE. However, I have zero confidence in trying this a third time with ATS On a good note, the install is clean. Their custom Bell housing works well and their translator seems to do a good job talking to the ECM

2014 ram 6.7, just installed aurora 3000 and ats exhaust manifold!! wow what an improvement in power and MPG, also in all fairness, banks super ram air filter, banks ram air intake and air charger tubes! dually mpg was around 13mpg before, yesterday from Walsenburg to pueblo co 20.5 mpg, and 18.2 coming back home!! No, it's not cheap to do this but, what's the price of a new truck!!!!!

I have a 2019 Ram 2500 with an ATS Allison transmission. I bought the transmission about 2½ years ago and had it installed by a local shop in Dallas. From day one it felt decent, but being an Allison, I always felt like I wasn’t getting the full experience I expected. I finally reached out to ATS Diesel Performance and spoke with Theo. After explaining what I was feeling, he told me to drive the truck up to Denver so they could look at it themselves. From that point on, my main contact was Cody. Cody’s communication was excellent from start to finish. He kept me updated the entire time and explained everything clearly. Once they inspected the truck, they found several small but important things that had been done incorrectly by the previous shop. Instead of cutting corners, ATS decided to pull the entire transmission and go through it completely. They opened it up, checked every detail, upgraded the clutches, and updated the transmission so it was fully up to date to ATS standards. When I flew back to pick up the truck, I honestly couldn’t believe the difference. It is night and day compared to how it drove before. I now realize how much I was missing out on for the last 2½ years. What impressed me most is that Cody and the entire ATS team did all of this at no cost. That level of integrity, pride in their work, and customer service is rare. ATS stands behind their product 100%, and it shows. If you’re running an ATS Allison or considering one, I can confidently say this is the only place I’d trust with it. Huge thank you to Cody, Theo, and the whole ATS team.

Clint Cody and everyone at ATS helped me get my duramax back to running immaculate and for a very competitive price and stellar installation and very quick turnaround. I would highly recommend that for your diesel needs you contact them and experience the star quality product customer service installation and price.

Bought the Allison stage 3 conversation for my 2015 ram 2500... absolutely garbage..the cheap lines blew apart in the first 700 miles the transmission does not shift well or consistent at all!!! I will NEVER buy anthor one or recommend getting it done.still waiting on them to figure it out an pay for the lines an nothing gets done because they don't care if you need to spend more money or break down.(I had a professional tranny shop put it in for me)

Cody at ATS handled the Allison conversion swap on my 2021 Ram 2500, and the service was top-notch. He kept me updated the whole time, answered every question, and made sure everything was done right. The install came out perfect and the truck drives amazing. Couldn’t ask for better customer service — huge thanks to Cody and the ATS crew!

So I have an 2007 Dodge 2500 with a 5.9 L Cummins. After looking around, I decided to go with the Ats Allison 1000 swap kit. They shipped it out to me. I installed it within a couple of days. It did have some issues to begin with once I got it installed. I contacted Ats and they began to help me troubleshoot the problems immediately we worked diligently for about 2 1/2 months to try and resolve these problems. At this point I talked with my contact at Ats and decided that the best course of action was to bring it to them. So I drove out to Denver. They had the truck for two days and now It works perfect. From what they explained to me, it has been very difficult to source quality parts from OEM manufacturers since Covid which entirely makes sense anybody who’s been involved in the Auto industry is well aware of these problems. From the moment I walked in to their facility, they went absolutely above and beyond to make it an amazing experience. they were nice enough to give me a complete tour of their facility, which was amazing. The tech that worked on my vehicle while I was there communicated to me the entire time. Not only did they fix the couple of issues I was having, but they also took the time to take care of a few other small issues and even hook me up with some upgrades on my truck and some free swag. Highly recommend picking up one of the hoodies, very comfortable. They even checked up on me over the next several days to make sure everything was working perfectly. if you are considering doing an Allison 1000 swap on your third GEN or any vehicle for that matter I highly recommend bring it to them not only will they make sure that it is perfect before it leaves but they will also make sure that you’re taking care of while you were there.

Showed up randomly to ats diesel. Cody greeted me,ask what I needed. Told him I pull dump trailers up 285with .you truck. Told him what it was doing. I originally wanted to by the adapter to test line pressure. But after we talked about valve bodies and torque converters. I decided to get one built. Cody got me a stage 2 with flex plate and they do rear main seals. I had a appointment the next week and got my truck that Friday. In and out said and done just under $9,500. 1year warranty. To sum up There knowledgeable, There efficient, There responsive I got a bunch of sweet ass stickers hoodies, shirts. IM HAPPY THANKS CODY

ATS stand behind their product , shout out to Cody I had problems they fixed it and I appreciate everything Cody and the owner did for me. They literally got me out the door within the 28 hour window. They busted their hump to make sure I was out the door Cody once again, I appreciate you so if you’re considering a transmission for your Cummins engine, give ATS Diesel performance a try they do stand behind the product 100% And they don’t play the blame game once again thank you Cody

My wife got me the thermal bypass and doomsday device after I talked with Cody about it. Cody took the time to walk me through the install even though both were very simple. I was told the importance of them both and while towing for work. I now have some peace of mind. Every thing helps. I’m extremely grateful for the knowledge that was provided to me.

Run—don’t walk—away from ATS Diesel Performance. This company has been nothing but a financial and mechanical disaster for me. After just 18 months, the first ATS Allison replacement transmission completely failed. I had to tow my truck from Wisconsin all the way to Denver for a replacement, only to drive it 1,000 miles back home and have it fail again the very next morning. It then took ATS five months to “fix” the issue, and they stuck me with another $4,000 bill. Between the two transmissions, I’ve now spent over $28,000—and the truck has only seen 50,000 miles in that time. That is an outrageous cost for a product that has proven to be unreliable, poorly supported, and ultimately worthless. To make matters worse, Nathan Grizzoffi, their General Manager, personally told me he’d get to the bottom of the issue and get right back to me. Nearly two months later—after repeated calls and emails—I’ve heard nothing from him or ATS. Empty promises, zero accountability. I’ve dealt with plenty of companies in my life, but this experience stands out as one of the most frustrating, disappointing, and infuriating. Save yourself the time, money, and misery. Do not trust ATS Diesel with your truck, your money, or your patience

Absolutely amazing! I have a 2018 Ram 2500 6.7L. Had ATS put on their VFR3000 turbo, pulse Flow Exhaust Manifold and Allison stage three transmission. Roughly two months and 7,000 miles ago. Cody and Makinzie both went above and beyond with service and always responding to emails, texts and calls. Really felt like everything was getting extra attention. Made me feel like my dream truck I ordered straight from Ram was getting taken care of the way I wanted. Went in with a date set for a pickup and on my way down to deliver my truck I started having other problems. ATS was still able to fix all the additional problems and put on the extra parts I ordered within that same time line. When a part was two or so weeks out, Cody thought outside the box and got me a part that same day without compromising anything. I will be back for more stuff even though they're 1400 miles away. They're all great people there loved working with them. P.S. Love the sound and performance of the new turbo. Also the amazing feel of the Allison transmission kit. Really grabs and shifts like it means to grab a gear and go.

Cody and his team did a phenomenal job once again! Got me in right away, had a full transmission replacement done in record time, and worked magic on the invoice & the service is always incredibly professional. Totally thrilled! Super happy, and always going back to ATS. Thanks guys!

Cody was my service advisor for some intake work on my truck. He was very communicative, and made the experience overall great. Cody made himself and ATS stand out when I called with a question and he was able to address me by name when he picked up. That is simply not customer service you see anymore.

Theo with ATS got me set up with an appointment to replace my transmission in my 2017 Ford powerstroke in a very short manner knowing I had to have it back quickly. He set me up with Cody who definitely has some of the best customer skills I've ever seen. Even after trailering my truck 520 miles and showing up 4 days before my appointment Cody made sure the truck was taken care of and actually had the install complete a day early knowing i had already purchased a plane ticket to go get it. Cody stayed in direct contact with me and if I had a question all I had to do was call and ask him! Great service overall and the product works fantastic!! Thanks Cody and the rest of ATS!!!

INCREDIBLE SERVICE! Cody has helped me through the process of buying my transmission and other services I’ve required! It’s been well worth the money with the top notch service I’ve received! Would recommend again and again!

ATS saved our family vacation!! We were 1000 miles from home when our truck started having transmission problems. I called Cody at ATS and explained our situation. He was able to get us in and his team diagnosed the issue immediately. We needed a new valve body. What I thought would take over a week, was finished in 3 days! Cody and the rest of the ATS team were absolutely amazing and had us back on the road. I 100% recommend ATS Diesel! They totally went above and beyond to help my family out. Thank you Cody!!

This ATS Thermal Bypass Valve isn't the cheapest on the market. However, with all the reviews and research, I find it to be the best out there. It will come with everything you need for your application to protect your investment. Installed in just about 20 minutes on the driveway. No vehicle lift is needed. Looks good and have already recommended to a couple of buddies! Think of it as a $100 insurance policy to save you $7000 and the downtime!!! Way to go #ATSDeiselPerformance!!!

I called ATS diesel to purchase a stage 5 Allison conversion kit for my 2016 RAM 2500 6.7 Cummins diesel i spoke with Kinsey a sales representative i asked some questions about the transmission with Kinsey she was very knowledgeable about ATS and there transmission so I purchased the stage 5 Allison i drove from California to Arvada Colorado to ATS diesel performance Kinsey got me a Uber driver to the airport and I flew home until my truck 🚛 was ready for pickup I flew back to Colorado and Kinsey got me a Uber driver back to ATS diesel performance and had my truck ready to go Kinsey is the best sales representative I have ever done business with great customer service. The Allison transmission is awesome 6 months later I went back to ATS diesel performance and purchased a Aurora stage 2 turbo and a ATS pulse full flow exhaust manifold from Kinsey she got me a Uber driver to my motel and when my truck 🚛 was ready for pickup Kinsey got me a Uber driver back to ATS diesel performance Kinsey is a value to ATS diesel performance Great sales representative and great customer service and my truck 🚛 felt so good to drive better fuel ⛽ milage and horse 🐴 power and 50 states emissions legal now that's TIT'S Up here are some pictures of my girl BIG TIT'S

Terrible customer service and a terrible experience. First all the first transmissions came without the flex plate. They blamed it on having a new shipper. And the transmission arrived on a palette that was hardly intact and 3/4 missing. I had to source a new one to return the core. I had to have three different transmission to me one after another because the first two were bad right off the gate. In addition they love to use helicoils way too much and their brand new product was contaminated with metal debris. I could literally go on for hours on explaining every last detail and have a mile of paper trail containing emails between us many of which they didn’t respond. Lastly I am supposed to be reimbursed for the last transmission fluid and labor costs for doing it a third time in a row. This has back in December. After several calls and emails I finally reached them and they just said sorry we didn’t see your emails and I must wait another three weeks for my reimbursement. What ever you do go to a different source for your transmission. I am kicking myself that I didn’t spend a tad more and go with a smaller solid company that better cares about their customer service. This has been a major headache that I have been dealing with for literally months almost a year. Attached are just a few pictures of my experience